In my project on the V120-22 I use 2 COM ports for RS485 Modbus communication. Port
2 - Master mode to communicate with another device, the Port 1 - Slave mode for
communication with the upper level.
After some time, the PLC stops responding via Port 1, while Port 2 is operating
normally and ladder is operating normally too. Helps only restart the PLC. If Port 2
is disabled, then the connection through Port 1 is without failing.
It seems, as if at the time of simultaneous access to the ports, there is a conflict.
Why lost communication with Port 1?
Port 2: 115200, 8, none, 2
Port 1: 57600, 8, none, 1
The request to Port 1 is sent after a pause of 10 ms after the last response
Connection breaks after 2000-15000 requests